1. Field of the Invention
This invention relates to a process for preparing butanediol and/or butenediol. More particularly, this invention relates to a process for preparing butanediol and/or butenediol in high yield by hydrolyzing diacetoxybutane and/or diacetoxybutene in the presence of a cation-exchange resin and distilling the hydrolyzed product to obtain butanediol and/or butenediol.
2. Description of Prior Art
Butanediols, particularly 1,4-butanediol are attracting more and more interests in recent years because they form polyesters with terephthalic acid which are useful molding materials having excellent physical properties. Further, butanediol is also useful as a starting material for synthesizing chemicals which are commercially valuable, such as tetrahydrofuran, .gamma.-butyrolactone or the like.
It is known that butanediol or butenediol can be prepared by hydrolyzing diacetoxybutane or diacetoxybutene. Use of a acid cation-exchange resin as the catalyst for the above hydrolysis is also known, but, when the acid cation-exchange resin is used for the hydrolysis, a part of the acidic segments of the resin is eluted in the resulting liquid. For example, if a strong acid cation-exchange resin having sulfo-groups is used, acidic substances such as --SO.sub.3 H radicals are eluted in the reaction liquid. Such acidic substances, even at concentrations as low as several parts per million in the liquid, may unfavorably affect the thermostability of butanediol and butanediol to a large extent and result in the formation of cyclic ether by-products such as tetrahydrofuran, etc., reducing the recovery of butanediol and butenediol.